Receiving system for electric waves or currents of constant frequency



Aug. 28, 1928. 1,682,533

Y. MARREC ET AL RECEIVING SYSTEM FOR ELECTRIC WAVES on GURRENTS OF CONSTANT FREQUENCY Filed June 1. 1922 I ventors Patented Aug. 28, 1928.

UNITED STATES PATENT OFFICE.

YVES MARREC, OF SURESNES. AND RENE FULDA, OF PARIS, FRANCE, ASSIGNORS,

BY MESNE ASSIGNMENTS, T0 MAR-REC LIMITED, OF LONDON, ENGLAND, A COR- PORATION OF GREAT BRITAIN.

RECEIVING SYSTEM FOR ELECTRIC WAVES 0R CUR-RENTS OF CONSTANT FREQUENCY.

Application filed June 1, 1922. Serial No. 565,070, and in France June 9, 1921.

This invention relates to a receiving system for electromagnetic waves or electric currents of constant frequency, and of a selective and antiparasitic nature.

It essentially comprises. among other elements or parts, one or more amplifying circuits of a su'liiciently aperiodic character comprising three-electrode audions or vacuum tubes or like devices, said circuits aflording the following results:

1. The electromagnetic waves are amplified (after amplification and detection) a. By superposing thereupon sustained oscillations such that their frequency shall be equal to that of the detected waves or submultiples of this frequency (so that the said sustained oscillations shall be harmonics of the detected waves) or a multiple of said frequency so that the detected waves shall be harmonics of the sustained oscillations). The superposition of these two waves will give rise to a resulting amplified wave whose period is equal to or different from the period of the detected waves, the two periods, old or new, remaining however in a simple ratio. a

b. By amplifying this resulting wave by means of a series of resonant amplifying circuits which are tuned to the length of said resulting wave.

2. Limitation is made in two or more of the amplification stages of the amplitude of the resulting wave by the saturation obtained by limiting the heating of the amplifying audions, or by like means for limitation of anmlitude.

The selection and the antiparasitic effect are afforded by the simultaneous action firstly of the amplification obtained by the superposition, upon the detected waves, of sustained oscillations of the same frequency or a frequency which is a multiple or submultiple of the same, and secondly by the limitation of the amplitude of the current by saturation or by like means.

The various steps involved in the present invention are as follows: After detection, sustained waves are superposed upon the signal waves and the parisitic waves. Since the period of the sustained waves is a multiple or a sub-mu1tiple of the signal waves to be received. the use (if the present inveii ticm results in obtaining, as concerns the received waves, resulting amplified waves of the same period or of a different period) as that of the signal waves. The effect of super-posing the local sustained wave is. in addition to the amplifying effect, a differentiation of the resulting sustained waves to be receved from the waves resulting from the parasitic effects.

The resulting waves are then amplified by a suitable number of audions which are coupled together by practically aperiodic circuits. These circuits provide for amplification and at the same time prevent the parasitic wave due to a damped wave from causing these circuits to vibrate at their proper period. since such vibration would set up oscillations tending to bring themnear the sustained oscillations which it is desired to receive.

The oscillations are then transmitted to resonant amplifying circuits which are tuned to the length of the waves resulting from the superposition of the local Wave upon the signal waves. In these circuits since the waves have already been sufficiently amplified by the superposition of the local waves and the aperiodic circuits. the saturation of the audions may be limited by regulating the heating current of the filaments so that the waves resulting from the parasitic waves whatever the intensity of the latter, are not given a greater amplitude than that given to the signal waves. In this manner the waves resulting from the parasitic waves may be eliminated by the use of a suflicieut number of resonant circuits. said parasitic waves being absorbed by the losses in the resonance circuits not adapted for the periods of the parasitic waves, which periods are different from those of the received signal waves. which latter alone are amplified by said resonance circuits.

This may be obtained for example by the arrangement of circuits which is shown in the accompanying drawing, the same being disposed after the detection circuit of any suitable receiving system. The arrangement of circuits as therein set forth represents simply the stages of an entire receiving system according to the present invention.

4 In the said diagram, a. indicates the eaten imflllIlftlSf of as d" c d wavesnf con- 1% .nt audible flequenii wants-meal by the parasitic waves, 12 the terminals of the succeeding. stage (amplifiers of the resonance type) not shown but which may be of any known or other suitable form containingandions coupled: through tuned circuits, 0 aperiodic transformers, 0 three-electrode audions, g the primary or storage battery for potential, 72 the heating storage battery, 7' the heating rheostat, 72: a heterodyn'e" of low frequency, and (l the induction coil of the latter.

The particularly important pointin this arrai'igementof circuits is the regulation of the heatingrot the atidions in order to limit he amplitude of the current by the satin-a fiioirof said audion's'.

In any extent, the? heatingoi "the audionsf should be so regulated that on the one hand the heatinfgsha ll' be safiieient to cause the sounds to remain audible with the diii'e'rpiit stagesofneaeferniation, and on the other hand the heating siiah besalficienuly lowered in order-to obtain sataaatien oi the requisite hiw degreeand hence t'o'elimi'natc para= site''efledts.

The present invention, however, is coitcerned with the case in which the parasites have'a greater amplitude than the signals if they'have a lesserainplitndeg they are not trodhlesome). Iasaeh alease the limitation aifects the parasites only, and the extent of the liniiation' is governed by the intensity of the saturation current which in its turn, depends on theheating of the filhment as is well known, so'th'at by regulating this heating theparasites'hiay he'cuti down to pr'aeti cally' the a/mplit ude'of the signal.

It is obvious that the hereinhero're described dcv-iccsare gia en solely-by way of example" ahd are not of a' limitative nature, and that they are-susceptible of'modifications withoutdeparting from the principle of the imentiom I'll paiticuianthe said arrange-- ment: has been disposed on the h'eterodyne system, hut-the same arrangement could be disposed on the autodyne system; on the other hand, the number of stages of ampli= fieat'ion-canbe increased. Inlikemaim'er, a; single-heating rheosathasbeeh provided, but

use may be made of a rheostat for each audion, and like devices can be employed.

What we claim is 1. The method of operating upon electrical signal waves of constant audible frequency accompanied byparasitic waves of greater amplitude and different frequencies after detection, which comprises superposing thereon sustained'loeal waves of a f're ucney hearing a simple ratio to that of the signal waves, passing the resultant waves through a nonresonant amplifier, and par-sing the waves from said amplifier through a SQCOIltl amplifier tuned to the frequency of the wares resulting-from the superpositionoi the local waves on the sigiial waves, while reducing the ratio of amplifieatiolr of waves above a given amplitude in proportion to the ratio of amplification of waves below said given amplitude to bring the amplitude of the amplified resaitants of the parasitic "awe down to substantially the level of the amplified resultantof the signal Waves.

2. The method of operating upon clcctrical= signal wavesof constant audihlie trequeney accompanied by parasitic waves of gl'ii'fitcl' amplitude and diil'eveat frequencies,

after detection, which comprises superposing thereon sustained local waves oi? a frequency hearing a simple ratio to that of the signal waves, passing the resultant waves through amplifier circuits containing midi ons coupled through non resmumttrans formers,- and passing the wares iromsaid amplifier circuits through a second set oi? amplifying circuits containing audion's and tuned to the frequency of the waves rosuiting from the superposition of theloeal warns on the signal waves, while regulating the heating of the filaments ot the :uulions to bring the amplitudeofi the amplified result ants of the parasitic waves down to suhsta'm tially the level of the amplified resultant of the signal wavesi In testimony whereof we 'huve'signed this specificati on.

YVES anatee. RENE FULDA. 

